The present invention relates to a body frame of a small-sized vehicle such as a motorcycle a motortricycle or the like, and more particularly to an interconnecting structure between frame elements forming a body frame of such a small-sized vehicle.
In the case of employing a pipe frame for a body frame of such a small-sized vehicle, upon connecting respective frame pipes, a lug is used and a lug and frame pipes are jointed together by welding or brazing, or else a lug is omitted and frame pipes are directly jointed together by arc welding. Not only are skilled operations necessitated for achieving such jointing, but also the frame pipes and the lug must be brought to a red hot state over a wide range, hence thermal strain is liable to occur and so the strain must be reformed after jointing. In order to carry out this type of work, special treatment equipment is necessitated, which increases an amount of work and brings about higher cost.
Moreover, when frame pipes made of light alloy material are used for a body frame of a small-sized vehicle, generation of blowholes within a welding metal, inclusion of slag, cracking by welding, etc. are liable to occur, and therefore a very skilled welding operative is necessitated.